Composition comprising a mixture of an elastomeric copolymer of butadiene and a thermoplastic copolymer of styrene and acrylonitrile and process for producing same



United States Paten s'Q ASTOMER IC 'I 'COPOLYMER F IBUTADIENE v xrnoo- P t a s F b-11 a .9 0.

ice

eepoi m'' se f hutadiene, 'acrylonitrile andyat m one further ethylenically unsaturated monomer, for thea mentioned blends, said 'c'opolymers contai' 'i'ng se' linking groups bound-to d further'monome'r'radical; Under self-cross-linking groups we understand such groups which effect cross-linkage of the copolymers When'heating the latter to temperatures of about 100- 1 220 C. such groups are for instance carbonyl groups,

Aktiengesellschaft, 'l leverku'sen, 'a corpora v 'tion of Germany 3 A e No g- Application July 3, 1956 Serial-No. 595,593 p I priority, application G-e'miah rui igis'ss 4 Claims (Cl. 260-455) The :present invention relates to new compositions of thermoplastic and elastic synthetic polymers, and'to, the production thereof.

such as carboxyl, carbonamid'e, aldehyde groups, furthermore methylol group-s, methylolether groups, dioxolane groups, ureido groups and groups of the formula:

i /O'0-R4 ,15 p 2 x i COR; 7

- iris whichki and R stand for ahydrocarbon ,zresiduc,

Thermoplastic syntheticpolymers, such )as polystyrene i or copolymers of styrene and acrylonitrile are; -.too;brittle for-many fields of application, because of their low im- .pact strength and impact strength notched. This-dis advantage can be substantially overcome ,by addition of rubberlike -elastomers -for instance copolymers of buta- 3 diene :and styrene or of butadiene and acrylonitrile to polystyreneor to thecopolymerpf styrene and \acrylor nitrile-(compare U.S.P. 2,439,202,) I

The aforesaid blends of high-molecular weight polymers have 'rcc'ently gained increasing technical importance.

As compared with thermoplastic polystyrene or the co- I polymer of acrylonitrile-and styrene, the said blends sh'ow besides increased ductibility-an iessentially,.improved nimpact strength and impact strength notched, whereas'othe'r mechanical properties, for instance their hardness; thermal stability or properties in the electric lfield :are only :slightly affected. However, on account 'of'their'zgre'ater hardness,

higher stability .to th erma'l influences, to solvents for rat- 1 in whichiR s'tandsfor hydrogen or alkyl, such i mospheric influences as well as itheirzcornpatibility'lwith taining acrylonitrile show considerable -advantages over mixturesof butadiene-andstyrene;

If, however, the rubber-likecopolymer of butadiene and acrylonitrile is entirely soluble in solvents such as toluene and methylethylketohe, the processing ofthe mixture of both elastomeric and thermoplastic polymers involves ditficulties. Articles of the aforesaid blends, which .are molded in the heat, show a substantial shrinkage and a lack of smoothness in their surfaces. Therefore, it has been proposed to partially cross-link the rubberlike: elastic component of butadiene and acrylonitrile before compounding this component with the thermoplastic 'copolymer of acrylonitrile and styrene by a thermal treatment at elevated temperatures on the rubber mill, or in an internal mixer, especially a Banburymill or by subjecting butadiene and acrylonitrile" to emulsion ipolymerization in the presence of a cross-linking agent such as divinyl benzene (compare U.S.-P. 2,550,139 and U.S.P.

The disadvantage of these processes is the long period rcquiredfor the thermal treatment and the resulting substantial discoloration of the-elastic copolymer'. Besides, the cross-linkage of the butadiene-acrylonitrile copolymer with divinylbenzene leads to the formation ofiblends having unsatisfactory mechanical properties if theftliermal treat'ment "step is omitted.

'In accordance with the present invention 'it has "been found that the disadvantages ;assoeiat ed with "the aforesaid'prio'r att'p'rocesses are overcome by using lastomeri'c other polymers containing polar groups, the blends conwhich {may be bound to the carbonyl groupby wayof a t-oxygm omu I For producing said copolymers lautadiene and acrylonitrile may be copolymerized with monomers containing said groups. Such monomers .are for instance:

(1) Ethylenically unsaturated carboxylic acids, such as acrylic acid, u-chloromethacrylic acid, methacrylic .acid, crotonic acid, sorbinic acid, *cinna'mic .acid,-. malei'c acid, maleic acid. monoalkylester. I

5(2). Amides of ethylenically unsaturated carboxylic acids, ,such as "acrylamide, .methacrylamide.

(3) Ethylenically unsaturated aldeh de's, such asacrO- lein; .methacrolein.

- -4, .1 Copolymerizable ethylenically unsaturateddnom omers containing at .least one methylol or methylolether group preferably of the formula: u

7 l 1 v voo l I-om0'R ethyL prQpyl, 'isfipropyl, butyl isobutyl, hexyl, and R for hydrogen," alkyl, ar-yl. Such monomers are for instance the alkylether of the rnethylol derivatives of acryla'rnide (compare Belgian Patent 539,963).

('5) Copolyrneri zable ethylenically unsaturated arers' qmainin at least one dioxolane residue in the molecule, asfor instance compounds of the formula;

in'which R .stands f or hydrogenor alkyl, R and Rg for hydrogen or ahydrocarbon residue, :such as alkyl, cy'clo allgyl, aryl.- Suitable compounds of this type meter instance,isopropylidene-glyceryl, acrylate and methacr'ylate, meth'yleneglyceryl acrylate and methacrylate '(corn pare U.S.P. 2,680,735).. t 1

, (6) Copolymerizable ethylenically unsaturated --mohov mers containing at least one ureido radical of the formula:

"NR CO- NI -IR f I in which R stand for H or ahydrocarbonresidue. Suitable compounds of this type correspond for instance :to the f ollowing formulaez.

cH qR .coo-A NH.co .:NH, I V in which R standsfor H or alkyl and A for an alkylene group, such as ethylene, propylene,. isopropylene. Such compounds are for instance: p-ureidoethylmethacrylate and acrylate (compare U.S.P. 2,694,695); (b CH =CH. O--ANR ;CO.N HR k in"which A stands for a cycloalkylene group or forfan ethylene group with 2-18 carbon atoms, and..R 7

hydrogen or a monovalent aliphatic or cycloaliphatic radical with 1-24 carbon atoms. Such compounds are disclosed in French Patent 1,075,898 and in U.S.P. 2,734,891. By way of example there may be cited: Ureidoethylvinyl ether, 3-ureidopropylvinyl ether, B-ureidoisobutylvinyl ether, N-cyclohexylureidoethylvinyl ether, N-(2-vinyloxyethyl)-N'-ethylurea.

(7) Monomers of the formula:

H2O=C C-Rs ll in which R, and R stand for a hydrocarbon radical, which can be bound to the carbonyl group by way of an oxygen atom. Such compounds are for instance the methylene derivatives of malonic acid esters, acylacetic acid esters, such as acetoacetic acid ethylester, acylacetones, such as acetylacetone. These compounds may be obtained by heating compounds of the general formula:

mixture is distilled off azeotropically and the residue is worked up in known manner.

The elastic copolmers used for the production of the blends of the present invention are preferably composed of 5-45 percent by weight of bound acrylonitrile, about 0.1 to 20 percent by weight of bound monomers with self cross-linking groups, the rest being bound butadiene. Copolymers of this type can be readily converted into an insoluble gelby heating them for a short period of time to temperatures ranging from about 140-170 C. The elastic copolymers are preferably produced by the process of emulsion polymerization according to known methods in an aqueous medium in the presence of catalysts, emulsifying agents and modifiers. Instead of butadiene there may be used homologues or derivatives of butadiene, such as isoprene. Moreover, it is possible to replace part of the mentioned monomers by other ethylenically unsaturated monomers, such as vinylchloride.

As pointed out above the elastic copolymers contain about 0.1-20 percentby weight of bound monomers with self-cross-linking groups. The preferred range is about l-10 percent by weight. In addition monomers which act as cross-linking agents when they are copolymerized with other monomers, such as divinylbenzene, glycoldiacrylate, may be used as copolymerizing components in the production of the elastic copolymers. Generally speaking, these monomers have no essential effect on the physical characteristics of the present blends.

These blends are preferably composed of about 10-75 parts by weight of the aforementioned elastic copolymers and of about 90-25 parts by weight of a thermoplastic copolymer, preferably of a copolymer acrylonitrile and styrene containing 5-45 parts by weight of bound acrylonitrile. These thermoplastic copolymers may be produced by the emulsion polymerization procedure as disclosed for instance in U.S. Patent No. 2,140,048 in an aqueous medium in the presence of an emulsifying agent, a polymerization catalyst and a modifier. q

The styrene in the above copolymers may be'replaced at' least partially by styrene derivatives, such as tat-chlorostyrene, 4-chlorostyrene, 2,4-dichlorostyrene. Furthermore, the above thermoplastic 'styrene-acrylonitrile copolymers may be replaced wholly or partially by other thermoplastic polymers, such as polyvinylchloride and copolymers of a major proportion of vinyl chloride with 4 w a minor proportion of another copolymerizable monomer as for instance vinylidenechloride, vinylacetate.

The blending of the elastic and of the thermoplastic copolymers is preferably carired out by mixing the latices of said copolymers as they are obtained by emulsion polymerization. These mixtures are then subjected to coagulation by well known methods. The coagulate is washed, dried and transformed into; the cross-linked state by heating it to temperatures of about 100-220" C. for a period of time as it is customaryon granulating the resulting powder. Moreover, the mixture of the latices may be compounded before coagulation with aqueous emulsions or dispersions of pigments, stabilizers and plasticizers. The process of the present invention is further illustrated by the following examples the parts indicated being parts by weight.

. EXAMPLE 1- 330 parts of a sheet of acopolymer consisting of-65% by weight of bound butadiene and by weight of bound acrylonitrile having a plasticity number (Defo value) 1350/35], are milled for 90 minutes on a roller mill the rollsof which are heated to 160 C. while the circulating sheet is cut from time to time. The copolymer assumes a strong dark-brown coloration. The proportion which has become insoluble in methyl ethyl ketone amounts to 60%. 670 parts of an acrylonitrile styrene copolymer containing 27.1% by weight of bound acrylonitrile as well as 50 parts of titanium dioxide (intrinsic viscosity of 1.20) is added within 10minute's on the roller to the pretreated copolymer. The blend-forms a smoothly circulating bright sheet. Test samples prepared from the blend show the physical propertieslisted in Table I. If the above copolymer of butadiene and acrylonitrile is replaced by a copolymer of butadiene, 35% by weight of bound acrylonitrile and 8% by weight of bound methacrylic acid of the plasticity number (Defo value) 1850/36.4, a proportion of 62% being insoluble in methyl ethyl ketone, is obtained within only 13 minutes at the same temperature, while the copolymer retains its original'light color. After compounding 670 parts of the aforesaid acrylonitrile styrene copolymerand 50 parts of titanium dioxide, test samples prepared from the mixture show .the test values indicated in Table I. Table I shows that the properties of the mixture with the elastomer component carrying carboxyl groups isat least identical with the mixture being free of carboxyl groups, though more than of the time required for cross-linking were saved.

Table I v PHYSICAL PROPERTIES OF THE BLENDS The above copolymerof butadiene andacrylonitrile is obtained in the following manner: 1

64 parts. of butadiene and 36 parts of 'acrylonitrile are emulsified in a solution of 5 parts of the sodium salt of an alkylsulfonic acid having about 16 carbon atoms in parts of wate r. To the emulsion therev are added 0.3 part of n-dodecy'lmercaptane and 0.1 part of the sodium, salt of .an alkylsulfinicacid having about 16 carbon atoms, whereafter thie pH-value is brought to 3 by addipercent ofthe monomersare copolymerized. The latex is stabilized by addition of 2-pa'rts of 'bi-(6.cyc'loliexyl-4- cresyl-2)-methane. The latexis 'coagulated in known manner, washed and 'dr-iedfi i For producing the corresponding copolymer containing carboxyl groups 56.5 parts of butadiene, 355 parts of acrylonitrile and 8 parts of niethacrylic acidare polymerized in the same manner as described above.

The above thermoplastic copolymer is produced as follows:

73 parts of styrene, 27 sified in a solution of 2 parts [of theabove emulsifying agent in 150 parts of water. After addition of 0.8 part of sodium metabisulfite and 0.4'part of potassium persulfate, and 0.2 part of n-dodecylinercaptane polymerization is carried through at 50 C.-and at a pH-value of 2-3. "After 95 percent of themonomers are'polymerized up as disclosed above.

EXAMPLE 2 If instead of the copolymer of 57 percent by weightof butadiene, 35 percent by. weight of acrylonitrile and 8 ketone while the copolymer retains its original light color.

When increasing the proportion ofmethacrylic acid in the, above copolymer to 12 percent by weight and I toneg By adding .700 parts of -a copolymer. of styrene and,28.5ypercent'" byweight of acrylonitrile of, thgjlk trinsic. :viscosity 1.02, and .25 parts" of titanium dioxide a blend is obtained, the physical properties of which are listed in Table III. When using a copolymer of butadiene, 35 percent by weight of acrylonitrile and 4 percent by weight of acrylic acid, having the plasticity number parts of acrylonitrile are emulpolymerization is interrupted and the latex is worked using the same amount of acrylonitrile it takes. only 9 minutes heating at 160 C. to produce a gel. having a proportion of 61.2 percent which is insoluble in methyl ethyl ketone. Afteradding 670 parts of the copolymer described in Example 1 consisting of acrylonitrile and styrene, as well as parts of titanium dioxide, test samples are prepared having properties listedin the following Table II:

I Table II 7 PHYSICAL PROPERTIES OF THE BLENDS Elastomeric oomponent Butadiene Butadiene acrylonitrile acrylonitrile with 4 parts, with 12 parts of methaof methacryllc acid crylic' acid Impact strength (kg. cm./cm. 106 Impact strength notched (kg. cmL/cmfl):

at 20 C 38 44 at O; 24- 26 at -15 C 8 12 Bounding strength (kg./cm. 710 760 Compression strength (kg/cm. 543 590 Tensile strength (kg/cm!) 416 v 445 (Defo. value) 1025/24.5., the reaction carried out at 165 C. requires only 9 minutes to'produc'e a gel-having an insoluble proportion of 70.3 percent in methyl ethyl 'ketone. The physical properties of thet mixture obtained from the gel under otherwise equal conditions with the acrylonitrile styrene copolymer areas wellcom piled in Table III.

CA er e 9 Tana er Q 'i Elastotne'ric Component in F I i 's-mans" Butadiene'. 'acrylonltrile' acrylonitrile with 4-partsof 4 I acrylic acid Impact strength (kg. cm./cm. 132* i 137 Impact Strength notched'(kg. cm

at 20 G 34 3 32 at 0 O 17 15 at 15 C; 6' 8 Bounding strength (kg./cm 815 862 Compression strength (kg/cm. 626 743 Tensile strength (kg/cm!) 460 493 .EXAMPLE .4

By treating, asdescribed in Example 1-, 325 parts of i a copolymer of butadiene, 35 percent by weight of'acrylonitrile, having the. plasticity number l000/25-.3-, on a rubber mill at C. for 82. minutes,@ copolymer is obtained which is insoluble to 60.5 percent inmethyl ethyl ketone. After compounding 675 parts ofja copolymer of styrene and 27.7 percent by weight of acrylo- 'nitrile of the intrinsic viscosity 1.25,- a blend 'is' obtained,

having the mechanical properties compiledin Table IV. If a copolymer of butadiene, 35 percent by weight of acrylonitrile and 2 percent by weight of methacrolein, having the plasticity number ,(Defo value); 675/195, is used instead of the above defined. elastbmericcomponent, the reaction. carried out at 160 C., requiresonly 24 minutes to. produce a product having an insoluble proportion of 61.3 percent of methyl ethyl" ketone; In

I 6 contrast to thezaforesaid copolymerionly avery slight discoloration occurs. 675 partsof-(the above acrylonitrile-styrene copolymer are thereafter compounded saidcopolymer blend. Theiigures of. Table: 4 showthat i the only slightlycolored blend containing;bound;-'meth acrolein possesses the sameproperties. as they are obtained from the butadiene acrylonitrile copolymeralthough the total processing timewassubstantially short- The copolymers of butadiene, acrylonitrile andjmetha ,crylic acid. are produced according to the process of :Example 1, while using 60.5 parts of butadiene, 35.5 {parts of acrylonitrile, 4 parts of methacrylic. acid, re-

spectively 52.5, 35.5 and 12 parts of said monomers.

' EXAMPLE 3 300 parts of a copolymer of butadiene and 35 percent. by weight of acrylonitrile having the plasticity num- :tially ,darkebrown colored copolymer has a gel proporperceut which is insoluble inmethyl ethyl. ke-

ened. 7

Table IV I p I PHYSICAL rn-ornn'rrns oFaHEnLE -Ds I Elastomeric Component I v Butadiene Butadiene acrylonitrile acrylonitrile with 2 parts oi methacrolein Impact strength (kg. cm./cm."). 111 108 Impact strength note :Ied (kg. cm./cm

at 20 O I 36 1 at 0 C; 15- 1 16 at l5 1]. Bounding strength (kg/cm. 720 730; Compression strength (kg/cm 542 505 Tensile strength (kg./cm. 41 0 'j'395' The copolymer containing bound methacrolein is prepared according to the prescription of Example 1, while using 62 parts of butadiene,.36 parts of acrylonitrile, 2 parts of methacrolein.

EXAMPLE 5 1000 parts of the 30 percent latex of a copolymer of butadiene, 35 percent by weight of acrylonitrile and 0.5 percent by weight of divinylbenzene, which latex is produced according to the prescription of Example 1, are mixed with 2058 parts of the 34 percent latex of a copolymer of styrene and 25.2 percent by weight of acrylonitrile, having the intrinsic viscosity 1.04, so as to obtain a proportion of 300 parts of the elastomeric component per 700 parts of the thermoplastic copolymer. After adding an aqueous dispersion of 50 parts of titanium dioxide, the mixture of the latices is coagulated by addition of common'salt solution, the coagulate filtered E and washed with water until the positive reaction on bound chlorine disappears. After drying at 80 C. a white powder is obtained from which 30 mm. thick strands'are obtained by molding by means of a screwpress heated to 170 C.,.having a screw diameter of 30 mm. These strands are comminuted to a granulate of 2 to 3 mm., diameter. The physical properties of this dried powder and of the granulate are compiled in Table V. The figures show'that the impact strength notched of samples prepared from the powder or the granulate is relatively low.

I Table V PHYSICAL PROPERTIES OF THE BLENDS Powder Granulate Impact strength (kg. cm./cm.=) 113 111 Impact strength notched (kg. cmJcmJ):

at 20 C 9. 0 9. 5 at 0 C 5. 0 B. 0 Bounding strength (lrgJem. 623 637 Compression-strength (kg/cm. 475 475 Tensile strength (kg/cm!) 390 380 EXAMPLE 6 Instead of the elastic copolymer described in Example 5, which consists of butadiene, 35 percent by weight of acrylonitrile and 0.5% by weight of divinylbenzene, 1025 parts of the 29.5 percent latex of the copolymer of butadiene, 35 percent by weight of acrylonitrile, 0.5 percent by weight of divinylbenzene, and 1.5 percent by weight of methacrylic acid are used. The latex is worked up in the same manner as disclosed in the foregoing example. The physical values of test bodies prepared from the powder and the granulate are listed in Table VI. The small amount of 1.5 percent by weight of methacrylic acid is responsible for the increase of the impact strength notched by more than 100 percent of the test body prepared from the powder in comparison with the values obtained when following the method of Example 5. However, the impact strength notched is increased to the value obtained in the manufacture of the blend from the isolated polymers on the rubber mill only by granulation at higher temperature (about 140 170 C.).

Table VI EXAMPLE 7 a I I, 1052 parts of the 28.5 percent latex of a copolymer-of butadiene, 35 percent by weight of acrylonitrile, 0.5 percent by weight of divinylbenzene and 3.0 percent by weight of methacrylic acid, which latex is prepared by emulsion polymerization according to the process of Example 1, are mixed with 2090 parts of the 33.5 percent latex of a copolymer of styrene and 20.0 percent by weight of acrylonitrile, having the instrinsic viscosity 1.2, so as to obtain a proportion 0f 300 parts of the elastomeric component per 700 parts of the'acrylonitrile-styrene copolymer. After adding an aqueous dispersion containing 25 g. titaniumdioxide, the latex mixture is coagulated and dried as described in Example 5. The following table shows the test values of thepowcler and the granulate prepared by the method described in Example 5. As shown in the preceding example, heating for a short period is sufiicient to substantially improve the impact strength notched of the test bodies.-

Table VII PHYSICAL PROPERTIES or THE BLENDS EXAMPLE 8 597 parts of the 29.3 percent latex of the copolymer of butadiene, 35 percent by weight of acrylonitrile, 0.5 percent by weight of divinylbenzene, and 3.0 percent of methacrylic acid are mixed with 583 parts of the 30 percent latex of a copolymer of butadiene, 26.0 percent by weight of acrylonitrile, 0.5 percent by weight of divinylbenzene and 3.0 percent by weight of methacrylic acid, as well as with 2004 cc. of the 32.3 percent latex of a copolymer of styrene and 25 percent by weight of acrylonitrile, having the intrinsic viscosity 1.15. The components are chosen so that the resultant mixture when isolated contains a proportion of 175 partsof the elastomeric component per 650 parts of the acrylonitrilestyrene copolymer. After coagulating the mixed latices as described in Example 5 test articles are produced from the powder formed as well as from the granulate obtained by the method of Example 5, which test articles show the values blend proves in the Table VIII below. On account of the larger proportion of the elastomeric component having a reduced acrylonitrile proportion, the blend-proves to be especially stable to low temperatures.

Table VIII PHYSICAL PROPERTIES OF THE BLENDS Powder Granule-ta Impact strength (kg. cmJcmJ) 86 82 Impact strength notched (k cm lcm at 20 C 32 53 at 0."- 27 50 at 15 C 14 44 at -3 O 8 26 Bounding strength (kgJcmfl)- 440 435 Com ression strength (kg/cm. 292 .185 Tensile strength (kg/cm!) 265 271 EXAMPLE 9 300 parts of a copolymer of 65 percent by weight of butadiene' and 35 percent by weight of acrylonitrile, having the plasticity number 1200/34.0, are milled for 85 minutes on a rubber mill the rolls of which are heated to C. while the circulating sheet is cut'from time to time. After this treatment the copolymer has a preportion of 65% which in insoluble in methyl ethyl ketone. The thus treated copolymer is then compounded within 10 minutes on the roll with 700 parts of an acrylonitrile-styrene copolymer of the intrinsic viscosity 1.3 containing 24.8 percent by 'weight of bound'acrylonitrile and 100 parts of titanium dioxide. Test articles prepared'from the mixture show the mechanical properties indicated in theTable IX (a). If instead of the aforesaid butadiene acrylonitrile copolymer, a copolymer of 61 percent of butadiene, 36 percent of acrylonitrile and 3 percent of methyleneacetylacetone, having the plasticity number (Defo value) 2000/35.0, is used a copolymer having an insoluble proportion of 61% in methyl ethyl ketone is obtained already after milling also 0. for.12 minutes. By incorporating on the. rolls within 10 minutes,700 parts-of the aforesaid styrene acrylonitrile copolymer and 100 parts ot-titanium dioxide a blend of the properties-indicated in Table IX (b) is obtained.

, Table. 1 X MECHANICAL PROPERTIES or THE BLENDS v -Butadiene Butadlene aerylonltrile aerylonitrile methylene acetylacetone vImpact strength (kg. cmJcrnJL. Inipact strength notched (kg. cm In.

. g at -G j g e th Compression strength g./em. Tensile strength (kg/cm?) The copolymer containing methyleneacetylacetone is obtainedin thefollowing manner:

61 parts of'butadi'ene,36 parts of acrylonitrile, 3 parts of methyleneacetylacetone are emulsified, in a solution of 5 parts of sodium alkylsulfonate (alkyl residue hav ing about 16 C-atoms) and 0.3 partof sodium pyrophosphate in ISO-parts of water;- "After addition of 0.6 part In Table X is shown that the process described this example produces within a veryshort time a materia having optimum mechanical properties.

EX MPLE 1 Similar to the process described in the preceding example the latices of anfelastomeric component, of a conventional methods.

of-"n-dodecylmercaptane, 0.3 part" of potassiumpersul- I fate the emulsion is-polymerized at a pH-value of 67;5 and a temperature of 2590; until percent of the.

monomers arepolymerized. The further procedure corresponds to that of Example'1.-

1 EXAMPLE 10 i 1000.- parts of a percent latex, obtained by emulsion polymerizationof butadiene, 35 percent by weight. of acrylonitrile and 0.5 percent of div'i'nylbenzene" having the plasticity number moo 37,0, are .mixedwith 2058 parts of the 34 percent latex of a copolymer of styrene," 20.5 percent by weight of acrylonitrile having an intrinsic viscosity 1.15., The eiastornericcomponent and the thermoplastic component arepresent in a proportion of 130570. After'adding 15,0 parts'of titaniumdioxide. in 't he form of an aqueous dispersion, the mixture.

is coagu lated by common salt solution, the resultant coagulate separated, washed ..unt il free of saltand dried at ".,C.1 The dried materialishomogenized onljmixing rolls; heated to 165 0., removed in'"strips and cut in i a beater mill. The material showsithe properties indi-' cated in Table X. If instead of the abovesaid elastomeric component, 915 parts of a 32.8 percent latex obtained by emulsion copolymerization of 61 percent by weight of butadiene, 36 percent by weight of acrylonitrile and 3 percent by weight of methyleneacetoacetic acid.

according to the process of the preceding example (P asthermoplastic component and ofan aqueous dispersion'of titanium dioxide are mixed, i.e. 923 parts off-a 32.5% latex ofthe copolymer of' butadiene, 35.5percent*by weight of acrylonit'rile and 3'percent by weight of methacrylamide=N-methylolmethyl ether (the copolymer having a plasticity number (Defo value) of'1900/45), 1892 parts of a37' percent latex of the. copolymer of 80 percent by weight of-styrene, and 20 percent by weight of acrylonitrile, having an intrinsic viscosity of and 100 parts of titanium dioxide in aqueous dispersion. As

described in the preceding example the mixture is pre-' .cipitated, washed and dried. The resultant crumbly material is gelled on ,a two-screw-extruding apparatus {and extruded in form of a sheet which can be granulated by In this manner arblend having the properties listed in the following'Table XI, is obtained. Table Impact strength (kg. cm lcmrfi) 102 Impact strength notched ('kg. con/cm?) X Al; 20 C. V 40 At 0" c i H 5.5 Bounding strength, (kg/cm?) 729 Compression strength, (kg./cm 448 Tensile strength (kg ;/em. 407 9 EXAMPLE 12 ticity number of the copolymer 1500/ 39.2), the material having the properties tai sd indicated. in Table X (b), is-ob-' Analogous to the process described in the. preceding example, 967 parts, of the 31 percent latex of a copolymer of 62 percentgby weight butadiene with 35 percent by weight of acrylonitrile' and" 3. p ercent by weight of methacrylic acid fi-u'rfeidoethyl ester, having a plasticity number '(Defo. value) of 1600/44..Q, are mixed with: 1892 partsof a317 percent latex of a copolymer of 79.3 percent; by weight of styrene with 20.7v percent byweight of acrylenitrildjhaving an intrinsic viscosity of 1.2 and worked up according to the process of' the preceding ex ample. The dried powder is compounded on a suitable internal mixing apparatus with partsof titanium dioxide, Whereafter the pigmented mixture is granulated as described in the preceding example. The blend shows the following properties:

Tensile strength (kg/cm?) 360 Table XIII Impact strength (kg. cm./cm. 92 Impact strength notched (kg. cm./cm.

At 20 C. 38

At C. 14 Bounding strength (kg/cm?) 660 Compression strength (kg/cm?) 450 Tensile strength (kg/cm?) 370 EXAMPLE 14 1000 parts of the 30 percent latex of a copolymer of 63 percent lay-weight of butadiene, 35 percent by weight of acrylonitrile and 2 percent of the ester of methacrylic acid and 4-hydroxymethyl-1.l-dimethyl-dioxolane, having 'a plasticity number (Defo value) of 900/ 34.5, are mixed with 1892 parts of the 37 percent latex of a copolymer of 80 percent by weight of styrene and 20 percent by weight of acrylonitrile and worked up as described in Example 10. The dried coagulate is then treated at 160 C. for 10 minutes on mixing rolls, removed in strips and comminuted to a granulate. Test articles having the following mechanical properties were produced at 240 C. by injection molding.

Table XIV Impact strength (kg. cmJcm?) 97 Impact strength notched (kg. cm./cm.

At 20 C. I 36 At 0 C. 12 Bounding strength (kg/cm?) 690 Compression strength (kg/cm?) 478 Tensile strength (kg/cm?) 362 mixture of (1) an elastomeric copolymer of 35-94.9

parts by weight of a butadiene, -45 parts by weight of acrylonitrile and 01-20 parts by weight of a further monoethylenically unsaturated monomer which is copolymerizable with butadiene and acrylonitrile, said further monomercontaining a cross-linking group which is selected from the class consisting of carboxyl, carbamyl,

methylol, ureido,

wherein R is alkyl and R is a member .of .the group consisting of hydrogen, alkyl and aryl,

wherein R and R are each members of the group consisting of hydrogen and hydrocarbon, and groups of the formula:

wherein R, and R stand for a member of the group consisting of (a) a hydrocarbon radical, and (b) a hydrocarbon radical which is bound to the carbonyl group thru an oxygen atom, and (2) a thermoplastic copolymer of 95-55 parts by weight of styrene and 5-45 parts by weight of acrylonitrile, said copolymer (1) being present in proportions of 10 to 75 parts by weight and said copolymer (2) in proportions of 90 to 25 parts by weight.

2. The composition of claim 1, wherein the elastomeric copolymer (1) contains-94parts by weight of a butadiene, 5-45 parts by'weight of acrylonitrile, and 1-10 parts by weight of said further. monoethylenically, unsaturated monomer.

3. The process for. preparing the composite thermo plastic mixture of claim 1 which comprises subjecting the elastomeric copolymer to a heat-treatment at temperatures heating the coagulate to temperatures of about to 220 C., until part of the elastic component (1) has become insoluble in toluene.

References Cited in the'file of this patent UNITED STATES PATENTS 2,439,202

Daly Apr. 6, 1948 2,442,588 DAlelio June 1, 1948 2,550,139 Daly Apr. 24, 1951 2,600,024 Romeyn et al. June 10. 1952 2,652,384 Sayko et a1. Sept. 15, 1953 2,698,313 Daly Dec. 28, 1954 

1. AS A NOVEL COMPOSITION, A COMPOSITE THERMOPLASTIC MIXTURE OF (1) AN ELASTOMERIC COPOLYMER OF 35-94.9 PARTS BY WEIGHT OF A BUTADIENE, 5-45 PARTS BY WEIGHT OF ACRYLONITRILE AND 0.1-20 PARTS BY WEIGHT OF A FURTHER MONOETHYLENICALLY UNSATURATED MONOMER WHICH IS COPOLYMERIZABLE WITH BUTADIENE AND ACRYLONITRILE, SAID FURTHER MONOMER CONTAINING A CROSS-LINKING GROUP WHICH IS SELECTED FROM THE CLASS CONSISTING OF CARBOXYL, CARBAMYL, 